1. Field of the Invention
The present invention relates to a vacuum cleaner. More particularly, the present invention relates to a multi-cyclone dust collector for a vacuum cleaner.
2. Description of the Related Art
Generally, a vacuum cleaner sucks dust-laden air that contains contaminants such as dust or dirt by suction force generated by a vacuum generator. When the dust-laden air passes through a dust collecting apparatus disposed in a main body of the vacuum cleaner, contaminants are separated from the dust-laden air and collected in the dust collecting apparatus. Then, clean air is discharged out of the vacuum cleaner.
The dust collecting apparatus that separates and collects contaminants from the dust-laden air may employ a dust bag, a cyclone dust collector, and so on. Currently, the cyclone dust collectors providing semi-permanent use have become widespread.
The conventional cyclone dust collector includes a cyclone body, an air inlet, and an air outlet. The cyclone body is formed in a cylindrical shape for the sucked air to whirl around therein. The air inlet is disposed at a side of an upper portion of the cyclone body in a tangential direction to the cyclone body for the air sucked through the air inlet to whirl downwards easily. The air outlet is disposed at an upper end of the cyclone body to guide the air, which whirls downwards and then rises up in the inside of the cyclone body, out of the cyclone dust collector.
However, in the conventional cyclone dust collector, the air whirling downwards collides with the air rising up in the cyclone body because both the air inlet and the air outlet are disposed at the upper portion of the cyclone body. Collision between the rising air and descending air decreases a dust collecting efficiency of the cyclone dust collector.
Furthermore, the conventional cyclone dust collectors cannot separate fine contaminants. In order to overcome the problem described above, the same applicant has invented and disclosed a multi-cyclone dust collector that separates fine contaminants being contained in the sucked air in two stages and provides a higher dust collecting efficiency, in Korean Patent Application No. 10-2003-0062520 (filed Sep. 8, 2003). However, the multi-cyclone dust collector still has a problem: the rising air colliding with the descending air decreases dust collecting efficiency.
Furthermore, in the conventional cyclone dust collector, a dust receptacle collecting contaminants is disposed below the cyclone body to share a same space with the cyclone body. Therefore, the contaminants being collected in the dust receptacle may flow back to the air outlet by the air that descends and then rises up in the cyclone body. The flow back of the collected contaminants deteriorates the dust collecting efficiency.